Cryotherapy for lentigo maligna — is clinical acumen combined with a single punch biopsy good enough for staging?

Aim We aimed to clarity the effectivenes of our staging of LM over a I-year period. Background Cryosurgery has become accepted as a simple and effective treatment for lentigo maligna (LM) but not necessarily lentigo maligna melanoma (LMM). Pigmented epithelial cells are extremely sensitive to cold injury. If adequate freezing is delivered to the proper depth into the dermal appendages, LM should be eradicated. However, if the initial staging does not detect invasion the lesion may be inadequately treated. Methods Over 1 year prospectively. all patients presenting with LM(n= 12) wore stayed clinically by experienced dermatologists and by a single punch biopsy. This was then checked by complete excision of the lesion. Results In 9 patients the clinical and punch biopsy diagnosis was confirmed after excision. Two melanomas were missed clinically but detected on punch biopsy. In one patient the punch biopsy described a “LM with probable invasion elsewhere in the lesion”. Surgical excision yielded a melanoma, 0.8 mm thick. Clark's level 4. In a second patient, punch biopsy diagnosed superficial spreading melanoma (-SSM) in situ, confirmed on excision. Conclusions We therefore feel that clinical diagnosis combined with a single punch biopsy will diagnose invasion when present. We emphasise that cryotherapy should not be performed without punch biopsy confirmation of the clinical diagnosis.